The present invention relates to a pneumatic tire, the weight of which is reduced with the steering stability and flow noise nature being maintained.
In order to reinforce the tread portion of a tire, it has been proposed to use a belt made of aramid cords. However, if only the aramid cord belt is disposed in the tread portion, the tire can not be provided with a sufficient rigidity because the aramid cords are weak in compressive stress in contrast with their very high tensile modulus and light-weight nature. As a result, the aramid belt tire is inferior in steering stability to a steel belt tire.
Further, due to the decreased tread rigidity, deformation and vibration of the tire are liable to occur during running, which results in increased tire noise.
As a countermeasure for such decreased tread rigidity it has been proposed to provide a steel cord belt together with an aramid cord belt. In this measure, however, the belt thickness is inevitably increased, and the tire weight is correspondingly increased.
It is therefore, an object of the present invention to provide a pneumatic tire, in which the tire weight is reduced, with the tread rigidity being maintained.